Access network discovery and selection function (ANDSF) is an entity in an EPC (evolved packet core) of SAE (system architecture evolution) for 3GPP (3rd generation partnership project) compatible mobile network. The ANDSF is introduced as 3GPP compatible user equipments (UEs) capable of accessing non-3GPP data networks increase. The ANDSF is responsible for a function of discovering a non-GRPP access network (e.g., wireless LAN (WLAN or WiFi), Wimax, etc.) used by a UE for a data communication in addition to a 3GPP access network (e.g., LTE (long term evolution), LTE-A (LTE-advanced), etc.) and providing rules and policies required for accessing the corresponding networks.
Depending on an operator's setup, ANDSF can provide a UE with inter-system mobility policy (ISMP), inter-system routing policy (ISRP), discovery information and the like. The ISMP can include a network selection rule for a UE to select a single active access network connection (e.g., WiFi, LTE, etc.). The ISRP can include a network selection rule for a UE to select at least one potential active access network connection (e.g., both WiFi and LTE). In accordance with an operator policy and user preferences, the UE may be able to use IFOM (IP (Internet Protocol) Flow Mobility), MAPCON (Multiple-Access PDN (Packet Data Network) Connectivity), NSWO (Non-Seamless WLAN Offload), or SIPTO (Selected IP Traffic Offload). The discovery information can include a list of available networks nearby a UE and an information helping a connection to the corresponding network.